I just lodged a complaint with the ACCC.
Indeed after the recent appeal I mentioned above I may actually be in the right according the kind lady on the phone.

I told her I indeed did prove it wasn't my system or user error, I have contacted the devs/publisher (a response on a forum counts apparently, especially if its an official response), I have told Valve all this in my refund requests that have been denied, even the recent one citing the ACCC's win in the courts recently.

She took down my details, told me that yes they ARE bound by AUSTRALIAN CONSUMER LAW in Australia especially after Valve's appeal loss, considering I have gone out of my way to prove the above things that THEY ARE REQUIRED to follow local laws if they're operating in Australia, even if its an online store ;)..... and that its getting looked into.